Imaging in nuclear medicine

• Bone scan: to look for stress fractures, inflammation, joint wear and tear, problems around a joint replacement or areas of bone affected by cancer.
• FDG PET scan (using a tracer similar to sugar): used in certain cancers to check whether the disease has spread and whether treatment is working. It is also used for some infections and inflammatory conditions, or neurological diseases.
• PSMA PET scan: used in prostate cancer.
• Heart scan: to check whether the heart muscle receives enough blood during stress and at rest. Other scans look for cardiac amyloidosis, a condition in which an abnormal protein builds up in the heart.
• Thyroid scan: to investigate an overactive thyroid or a thyroid lump.
• Kidney scan: to measure how well each kidney works, often in children.
• Lung scan: to look for a blood clot in the lungs, called a pulmonary embolism.
• Brain imaging: used to investigate memory problems or Parkinson’s disease.
• Sentinel lymph node mapping: before surgery for breast cancer or melanoma, to find the first lymph node or nodes that need to be checked.

1. Welcome and checks. The technologist or nurse checks your details, explains the test and asks a few questions, including about your medicines, pregnancy and breastfeeding.
2. Receiving the tracer. This is usually a small injection into a vein in your arm. You will normally only feel the needle prick.
3. The tracer needs time to reach its target. This can take a few minutes to several hours, depending on the test. Before a PET scan, you rest quietly in a chair or on a bed. For some other tests, you may be able to leave the department and return later.
4. Taking the images. You lie on a scanning table and need to keep still, usually for 10 to 45 minutes. You can breathe normally.
5. You can usually go home and return to your normal activities, including driving. The technologist or nurse will inform you of any measures that need to be followed after the exam

Allow one to four hours for the whole appointment, sometimes longer. Some tests take place in two parts over two days. Feel free to bring something to read.

Preparation depends on the test. Always follow the instructions your hospital gives you. Common instructions include:

• Fasting: for example, not eating or having sugary drinks for several hours before an FDG PET scan. You can usually drink plain water.
• Medicines: for some heart or thyroid tests, you may need to stop a medicine temporarily. Never do this without your doctor’s agreement.
• Coffee, tea and chocolate: you may need to avoid these before certain heart tests.
• Diabetes: tell the department in advance, especially before an FDG PET scan.
• Clothing: wear comfortable clothes, preferably without metal parts.
• Pregnancy and breastfeeding: always tell the department when booking if you are pregnant, could be pregnant or are breastfeeding.

If you find it difficult to lie still, feel anxious in enclosed spaces or are in pain, tell the team. They will work with you to find a solution.

A small amount of radioactivity remains in your body for a while after the test. A few simple precautions may be needed:

• Drink enough fluids and go to the toilet regularly to help the tracer leave your body.
• Wash your hands thoroughly after using the toilet.
• If advised by the team, limit close, prolonged contact with young children and pregnant women for the rest of the day.
• If you are breastfeeding, ask whether you need to pause and for how long. This depends on the tracer.
• If you are flying in the next few days, airport radiation detectors may pick up the tracer. Ask the department for a certificate.

Children can also have nuclear medicine tests. The amount of tracer is adjusted to their weight. A parent can usually stay with their child during the test. The teams are used to helping children feel at ease. A favourite cuddly toy, a tablet or a story can often help them keep still.

This information is general and does not replace advice from your doctor. Always follow your hospital’s instructions.